Liquid distributing system for dishwashing machine



June 6, 1967 c. GEIGER ETAL 3,323,529

LIQUID DISTRIBUTING SYSTEM FOR DISHWASHING MACHINE Filed July 26, 1965 .2 Sheets-Sheet l FIG-1 I N VEN TORS RUSSELL c. GEIGER, PAUL a. GEIGER a Y DAVID A.MEEKER B 39 M /W ATTORNEYS June 6, 1967 R. c. GEIGER ETAL 3,323,529

LIQUID DISTRIBUTING SYSTEM FOR DISHWASHING MACHINE Filed July 26, 1965 2 Sheets-Sheet ;1

I50 FI G "'3 54 1 I86 I [56 5 I59 '8 [65 66156 FIG4 89 60 ez 25 83 I '70 United States Patent 3,323,529 LIQUID DISTRIBUTING SYSTEM FOR DISHWASHING MACHINE Russell C. Geiger, Paul B. Geiger,

Troy, Ohio, assignors to The Hobart Manufacturing Company, Troy, Ohio, a corporation of Ohio Filed July 26, 1965, Ser. No. 474,667

10 Claims. (Cl. 134--104) This invention relates to a liquid distributing system for dishwashing machine, and more particularly, to an improved system for recirculating filtered wash and rinse water over the articles placed in a household or a small commercial dishwasher.

In dishwashers of this general character the soiled dishes or other articles are placed within racks supported within the cleansing chamber and are subjected to washing and rinsing sprays produced by a liquid distributing system, commonly referred to as a wash system. The detergent wash water and clean rinse water are recirculated for a time sufficient to loosen and remove the food particles from the dishes, or the like, so that when the water is drained from the cleansing chamber after each wash and rinse period, the particles will be carried along with the liquid.

To conserve on hot water used in the machine and to produce an effective cleansing system, it is desirable to recirculate the liquid over the articles. Furthermore, it is desirable to avoid the recirculation of the food particles to prevent redeposition of the particles on the dishes. To accomplish this, it is necessary to separate the food particles from the liquid while it is being recirculated. For this purpose, preferably, a filter having relatively fine openings is employed and is so constructed and spaced that the liquid returning to the main recirculating pump will continuously flush the filter to minimize the collection of food particles.

It has also been found desirable to provide a dishwashing machine with a drain pump which can operate simultaneously with the main recirculating pump during draining so as to receive the liquid carrying the food particles flushed from the fine strainer to discharge the liquid to a suitable drain line at the end of each wash and rinse period. Often the main recirculating pump and the drain pump are driven by two separate motors so that the operation of each pump can be controlled independently of the other. On the other hand, for economical construction of the wash system, it is desirable to drive both pumps by a single motor to avoid the extra cost of a second motor. Furthermore, it has been found desirable, from a servicing standpoint, to provide a liquid distributing system which can be quickly and easily disassembled to enable conventient replacement of the components which are most likely to wear.

Accordingly, it is one primary object of the present invention to provide a novel and improved liquiddistributing system for a dishwashing machine wherein the food particles are separated before the liquid enters the main recirculating pump and are flushed by the liquid to the inlet of a drain pump which is driven by the same motor driving the recirculating pump whereby both pumps may ope-rate simultaneously for a predetermined period to provide an effective flushing of the filter and cleansing chamber during draining.

Another object of the present invention is to provide an improved liquid distributing system for a dishwashing machine as described above, wherein the inlet for the main recirculating pump is surrounded by a finely perforated filter having a portion extending above the dynamic liquid level within the wash chamber to provide a continuous outward flushing action over the exterior surface of the filter to prevent food particles from clogging the openings within the filter.

and David A. Meeker,

Still another object of the present invention is to provide a novel liquid distributing system as described above wherein the inlet for the main recirculating pump is spaced at the top of the pump substantially in the center of the cleansing chamber to provide for a smooth uniform flow and quick return of the liquid into the pump Without turbulence so as to minimize the volume of liquid required for effective air free operation of the pump.

It is also an object of the invention to provide a liquid distributing system as described above wherein a reaction spray arm is rotatably supported by a conduit member above the main recirculating pump and is constructed in such a manner that the liquid flowing into the spray arm produces a reaction downward force on the spray arm to hold the arm firmly against a horizontal supporting surface so that the arm will .not move upwardly out of its sealed relationship with the conduit.

As a further object, the present invention provides a liquid distributing system as described above wherein a novel rotary sealing means is to provided between the reaction spray arm and its supporting member to prevent seepage of liquid having extremely fine solid food par ticles and thereby eliminate possible jamming of the rotation of the spray arm.

Other objects and advantages of the invention will be apparent from the following description, the accompanying, drawings and the appended claims.

In the drawings:

FIG. 1 is a side elevational view of a typical dishwashing machine incorporating a liquid distributing system in accordance with the invention;

FIG. 2 is an exploded view of the liquid distributing system shown assembled in the machine in FIG. 1;

FIG. 3 is an elevational view in axial section of an assembled distributing system as shown in FIGS. 1 and 2;

FIG. 4 is an enlarged detailed view in axial section of the assembly of the impellers to the motor shaft;

FIG. 5 is a fragmentary plan view of a typical jet opening formed within the spray arm; and

FIG. 6 is a section View of a spray tube as viewed along the line 5-5 of FIG. 4.

Referring to the drawings, which illustrate a preferred embodiment of the invention, FIG. 1 shows a typical front loading type dishwasher including an outer cabinet indicated generally at 10 which encloses a tank 11 having a bottom 12 to define a wash chamber 14. Access to the 7 it is to be understood that the liquid distributing system according to the invention may be employed in other types of dishwashing machines, as for example, a top opening portable dishwasher.

As shown in FIGS, 1 and 2, the bottom 12 is sloped downwardly towards the center so that the liquid collecting thereon drain into the sump 26 having an annular step 22 and a bottom 23 having a central opening 24. Mounted directly below the bottom 23 of the sump 20 is a drain pump having a housing 25 which is located by an annular flange 26 extending through the opening 24 and is secured to the bottom 23 by the screws 27 (FIG. 3) extending through a series of holes within a support plate 29 and corresponding holes within the bottom 23 and annular flat gaskets 32 and 33. The screws 27 are threaded into the housing 25 which preferably is formed from a suitable thermosetting plastic material.

Mounted below the drain pump housing by a series of uniformly spaced screws is a motor 38 having leads 39 (FIG. 2) and a top bearing bracket 40 (FIG. 3) which is provided with a corresponding series of threaded holes to receive the screws 35 extending downwardly through the housing 25. Accurate alignment is provided between the drain pump housing 25 and the bearing bracket 40 by the counterbore seat 42 formed within the bottom of the housing 25 for receiving the four stepped flanges 43 formed on the top of the bearing bracket. As shown in FIG. 3, the motor 38 includes a stator 45 supported within a cylindrical shell 46 which, in turn, is clamped between the upper bearing bracket 40 and the lower bearing bracket 49 by four uniformly spaced motor screws 52. A rotor 54 is attached to the motor shaft 55 by a suitable tolerance ring 57 and the entire rotor and shaft assembly is rotatably supported by the ball hearing 60 retained Within the hub 62 of the lower bearing bracket 49 and the ball bearing 64 retained within the hub 66 supported by the upper bearing bracket 40 through the radially extending ribs 67.

A centrifugal fan impeller '70 is spaced between the bottom of the drain pump housing 25 and the top of the bearing bracket 40 and is mounted on the shoulder 72 (FIG. 4) formed on the motor shaft. The fan impeller is provided to cool the motor 38 by sucking air through openings 73 (FIG. 2) in the bottom bearing bracket 49, up through the motor and the space provided between the ribs 67 and through the top opening 74 defined by the annular lip 75 extending upwardly from the upper hearing bracket 40. The air is then discharged outwardly through a series of openings 77 provided between the flanges 43 on the upper bearing bracket 40.

The cooling impeller or fan 70 is formed as an aluminum die casting and includes a hub 79 (FIG. 4) which seats against the shoulder 72 of the shaft 55 and encloses an O-ring 80 which engages the shaft shoulder 81. The impeller 70 also includes a top hub 83 which extends through the shaft seal 85 and the ceramic seat 89 to space the drain pump impeller 90 by suitable spacing washers 91.

As a result of this construction, the cooling impeller or fan 70 also serves as a water flinger when the motor is running in case any water should happen to seep between the shaft seal 85 pressed within the bottom of the drain pump housing 25 and the ceramic seat 89 pressed into a resilient lining within the counterbore formed within the bottom surface of the drain pump impeller 90. Furthermore, if a leak should occur when the shaft 55 is not rotating while water is within the sump 20, it will be seen that the water will run down along the outside of the hub 83 of the cooling impeller '70 and then radially outwardly along the top surface of the impeller '70 to drip off the downwardly extending peripheral edge 92 onto the downwardly sloping top surface of the upper bearing bracket 40. The downwardly formed rim 93 formed as an integral part of the upper bearing bracket 40' prevents any water droplets from running down into the inside of the motor 38.

Mounted above the bottom 23 of the sump 20 is the housing 95 of the main recirculating pump which is spaced from the bottom 23 by four legs 97 which seat on the annular top cover 99 mounted on the drain pump housing 25 and thereby defines a lower drain passageway 100. A series of four uniformly spaced screw 102 extend through the legs 97 and are threaded into the drain pump housing 25 sandwiching therebetween the drain pump cover 99.

Rotatably mounted within the main recirculating pump housing 95 is an open type centrifugal impeller 105 having upwardly extending vanes 106 and which is rigidly secured to the upper end of the motor shaft 55 by the drive washer 107 having engaging ears 108 and a central opening which corresponds to the pair of opposed flats 109 formed on the end of the rotor shaft 55 and thereby positively locks the impeller 105 to the upper end of the motor shaft 55. A screw 112 and cap washer 113 serve to retain the main recirculating impeller 105 to the motor shaft 55. The bottom hub 115 of the main impeller 105 is provided with a pair of diametrically opposite projections 117. These projections 117 engage corresponding openings within the top of the hub 120 of the drain impeller 90 to drive the drain impeller. A a result of this driving arrangement of the impellers 105 and 90, it can be seen that by removing the drive washer 107, the shaft 55 can be manually turned from the top to free the impellers on the shaft should the impellers become somewhat frozen after an extended period of use.

Formed within the housing 95 of the main recirculating pump are a pair of diametrically opposed volute shaped passageways 124 having curved ramps 125 (FIG. 2) at the ends, which change the direction of the water discharged from the main impeller 105 from a radial direction up through a pair of diametrically opposed openings 127 formed within the cover 128 secured to the housing 95 by four screws (not shown) extending through the openings 129. Similarly, the cover 128 is provided with a pair of corresponding passageways under the ramps 131 (FIG. 2) which mate with the passageways 124 to maintain a generally uniform cross sectioned area for the How of liquid from the pump. Centrally located within the cover 128 is the inlet opening 132 which permits the water to flow down into the eye of the impeller 105.

Mounted Within the tubular bosses 135 formed upwardly on the cover 128 and which define the openings 127 is a manifold 137 which directs the water from the main recirculating pump through the conduits 139 from which the water flows together in the annular discharge passageway 141 defined by the cylindrical portion 142 extending at the top of the manifold. Preferably, the manifold 137 includes the bottom projections 143 which are suitably cemented within corresponding counterbores 144 formed within the top of the bosses 135 of the pump cover 128.

Mounted within the hub 146 centrally formed on the under side of the manifold 137 is a shaft 148 which rotatably supports a reaction spray arm 150 by a sleeve type bearing 152 mounted within the top portion of the hollow hub 154 of the spray arm. As shown in FIG. 2, the spray arm includes four equally spaced closed end tubes 156 which extend horizontally from the hub 154 and are retained therein by clamping the tubes within corresponding openings 157 (FIG. 3) formed by fastening the upper portion 159 of the hub 154 to the lower portion 160 by a series of screws 162. Preferably, the hub 154 is formed from a suitable thermosetting plastic material and the four tubes 156 are formed from a stainless steel material to prevent corrosion of the spray arm 150 by the strong alkali detergents placed in the cleansing water used in the dashwasher.

As shown in FIG. 6, the tubes 156 are formed by crimping the upper portion 163 to the lower portion 164 around the center of the tube. Formed within the upper portion of the tubes 156 are a series of spherical impressions 165 each having formed therein a jet opening defined by an elongated slot 166 positioned normally to the axis of the tube. This configuration of the jet opening has been found to produce a relatively flat spray in a vertical plane substantially 90 to the position of the slot 166. This flat spray results from the curvature of the impression 165 since the stream of water discharged from each outer end of the slot 166 is directed radially inwardly from the spherical surface of the impression 165, thus causing the streams of water to focus on the central stream discharged from the center of the slot and causing the combined stream to flatten in a position substantially at right angles to the direction of the slot 166.

This relatively fiat stream is preferred so that the overall spray produced by the several jet openings 166 within the spray arms 150 is distributed uniformly over the dishes and other articles to be cleansed. Furthermore, it has been found that by using four tubes 156, the several jet openings can be spaced apart to avoid more than one jet stream of water being directed against a particular article at any one time. This, in turn, prevents the high pressure spray from two or more jet openings 166 from combining to be directed against a light article, as for example, a cup or light glassware, causing this article to be tossed around within the supporting rack. This distribution of the water stream is especially important when a relatively high pressure recirculating pump is employed as is provided by the centrifugal pump of the present invention. There is also a similar jet opening 170 formed within the upper portion 159 of the hub 154. This jet provides a spray coverage for the central area directly above the hub 154 which otherwise may not be covered. The other jet openings within the tubes 156 are each spaced a predetermined radial distance from the central axis of rotation so that the combined overall upwardly directed spray coverage is substantially uniform.

To support the wash arm 150 at the desired elevation on the shaft 148, a cylindrical hub portion 175 is formed as an integral part of the upper portion 159 of the hub 154 and projects downwardly therefrom to define an annular bottom horizontal bearing surface 177 which engages a corresponding surface or seat 179 formed on the deflector member 180 secured to the shaft 148 by the pin 181.

As shown in FIG. 3, the bottom surface of the deflector member 180 is provided with an annular curved por- 182 which changes the axial flow of Water through the annular passageway 141 from an axial direction to a generally radial direction so that the flow of water is directed against the sloping surface 184 formed within the lower portion 161} of the hub 154. This dynamic pressure caused by the flow of water against the surface 184 produces a downward reaction force on the hub 154 which has been found desirable during the initial flow of the water to cause the bearing surface 177 to firmly engage the seat surface 179 of the deflector member 181) and thereby prevent the spray arm 159 from raising upwardly or blowing off the supporting shaft 148. It has also been found desirable to provide relief passageways 186-within the hub portion 175 to prevent a pressure build up under the hub portion 175 and lifting the spray arm 150 upwardly on its supporting shaft 148.

Another cylindrical hu-b 190 is formed as an integral part of the lower portion 160 of the spray arm hub 154 and extends downwardly to surround the upper cylindrical portion 142 of the manifold 137. Formed within the exterior surface of the cylindrical portion 142 is a circumferential groove 192 in which floats a split type sealing ring 193 (FIGS. 2 and 3) which preferably is formed as a sintered bronze part to provide high resistance to wear. This sealing ring 193 is adapted to engage firmly the inner cylindrical surface of the hub portion 190 and thereby rotates with the spray arm 150 within the groove 192.

It has been found that this sealing construction substantially eliminates the seepage of water through the annular clearance gap between the hub portion 190 and the cylindrical upper portion 142 of the manifold 137. The outer diameter of the deflector member 180 is slightly less than the inner diameter of the cylindrical hub portion 190 of the spray arm 150. This permits the spray arm to be removed simply by manually lifting the spray arm off the shaft 148. Then of course, to place the spray arm 150 back in position, it is simply centered on the shaft 148 and lowered downwardly until the bearing surface 177 engages the seat surface 179 and the sealing ring Will slide into the hub 190.

Formed within the bottom of the lower portion 160 of the hub 154 is an annular groove 195 defined in part by an annular flange 197. Spaced substantially midway Within the groove 195 and covered by the flange is the cylindrical upper lip 1 99 of a frusto-conical shaped fine strainer or filter 200 which surrounds the manifold 137 and serves to filter the coarse and fine food particles from the water which enters the inlet 132 of the main recirculating pump. Preferably, the fine filter 200 is formed from a stainless steel material having a high concentration of small perforations of approximately .045 inch in diameter.

The bottom portion 203 of the fine filter 200 is formed of the same material and has a somewhat bowl shaped configuration having an annular horizontal portion 204 and a vertical rim 205 which fits snugly over an annular seat 206 formed on the cover 128 of the main recirculating pump. In this manner the fine filter 200 is concentrically spaced within the supporting shaft 148. An opening 207 is provided in the outer wall of each of the tubular bosses of the cover 128. These openings have been found to serve two functions. First, they permit the free drainage of water held in the manifold 137 and spray arm by the rotating impeller near the end of the drain period. Furthermore, it has been found that the small streams of water directed from the openings 207 during operation of the main pump serve to help flush the lower portion of the filter 200* and also provide a slight rotation of the fine filter during recirculation of the water. This rotation, in turn, provides for more uniform flushing of the conical surface of the filter.

Surrounding the fine filter 200 and bridging the annular space between the conical portion of the filter 201) and the inner surface of the sump 20 is a coarse strainer 210 having substanitally larger perforations 211 of approximately y inch in diameter. The coarse strainer 210 is provided with an inner upwardly extending annular flange 214 which conforms to the conical configuration of the fine filter 200' and rests snugly thereon. The outer periphery of the coarse strainer 210 is defined by an upwardly sloping flange 216 which engages the wall defining the sump 20 and thereby cooperates with the close fit between the inner flange 214 and the fine filter 2% to prevent relatively large insoluble food particles from entering the sump 20 and from clogging the drain passageway ]ltlfi or jamming the drain pump. As a further protection from preventing large solid food particles or foreign objects from entering and damaging the drain pump, a series of uniformly spaced ribs 221 are provided around the periphery of the cover 128 and spaced adjacent the step portion 22 of the sump 20 to define passageways 223 (FIG. 3) of predetermined size corresponding to the maximum size particles which can be handled within the drain pump.

It has been found that by maintaining the dynamic water level slightly above the top of the coarse strainer 210, a level indicated by the line 218, during the operation of the main recirculating pump, there is a flow of liquid downwardly and outwardly along the exterior surface of the fine filter 200 which causes the fine and coarse food particles stopped by the filter 200, to flow down onto or through the coarse strainer 210. Furthermore, since the main pump is still recirculating liquid during the first portion of the drain period and until the liquid level drops below the inlet of the main pump, the fine filter 200 continues to be flushed during the first portion of the drain period. However, only the food particles which can pass through the openings 211 within the coarse strainer 216 will collect in the lower portion of the sump for removal by the drain pump during the drain period of the dishwashing cycle. The larger food particles which will not dissolve, as for example, a bone particle, will collect on the coarse strainer 210 and can be easily removed from the machine simply by raising the spray arm 150 and removing the coarse strainer.

To eliminate the disturbing noise produced by the repetitive starting and stopping of the main motor 33, it

is preferred that the motor be operated continuously throughout the wash, rinse and drain periods of the cycle and is not shut off until the drying period of the cycle begins. Thus, it can be seen that since the drain pump is continuously running, liquid would continuously drain from the cleansing chamber 14 unless some means was provided to prevent the flow of liquid through the discharge outlet 222 extending from the drain pump housing 25. For this control, a suitable solenoid operated drain valve 225 (FIG. 1) is connected with its inlet to the discharge outlet 222 by the resilient tube 227 which is tightly connected by the clamps 228. The outlet of the drain valve 225 is, in turn, connected by the drain hose 229 to a suitable drain line. The operation of the solenoid drain valve 225 is controlled by a suitable timer (not shown) which also serves to control the separate operation of the fill valve (not shown), the motor 38 and the drying system (not shown) according to a predetermined programmed sequence.

From the drawing and the above description, it can be seen that the liquid distribution system according to the invention, combines several desirable features. Specifically, both the main recirculating pump and the drain pump are operated by a single motor and are so arranged and constructed that the inlet to the main recirculating pump receives only liquid which has been filtered through a fine filter so that food particles are not recirculated and redeposited on the dishes and other articles. Furthermore, the food particles which are separated from the recirculated liquid are directed through a coarse strainer into the drain pump for removal from the machine. It has also been found that the frusto-conical shaped fine strainer, having a portion extending above the dynamic water level, serves as an effective self-flushing filter for removing fine food particles from the liquid recirculated by the main pump. Furthermore, by extending the top portion of this fine filter into an overlapping relationship with the hub of the spray arm, it has been found that an effective labyrinth seal is provided whereby liquid containing food particles is prevented from splashing over the top of the strainer and thereby entering the main recirculating pump.

Another important advantage is obtained by the ef fective seals provided between the hub 154 of the spray arm 150 and the stationary seat portion supported by the manifold 137. That is, the upper rotary horizontal seal cooperates with the lower cylindrical seal provided by the sealing ring 193 to prevent minute solid food particles from jamming the free rotation of the spray arm 150. Also, by providing the relief passageways 186, a liquid pressure build up is prevented which would force the spray arm 150 upwardly to an inoperative position.

In addition, the angular sloping surface 184 formed within the hub 154 redirects the flow of liquid which, in turn, exerts a downward reaction force on the hub 154 causing the spray arm 150 to be held downwardly against the stationary seating surface, especially when the high pressure flow of liquid is first discharged into the spray arm from the main recirculating pump.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

l. An improved liquid distributing system for a dishwashing machine having a tank defining a cleansing chamber with a sump at the bottom and adapted to separate fine food particles from the liquid recirculated within the chamber, said system comprising, a main recirculating pump mounted within the sump and having an impeller positioned with a vertical axis of rotation, means defining an inlet opening spaced above said impeller, a re action spray arm spaced above said main pump, manifold means connected to said pump and rotatably supporting said arm with a vertical axis of rotation, a fine filter surrounding said manifold means and said inlet opening and having at least a portion adapted to extend above the dynamic water level within the sump, a drain pump spaced below the sump and including an impeller and means defining a drain outlet, means defining a passageway connecting the sump to said drain pump impeller and adapted to direct liquid containing relatively large food particles flushed outwardly down the outside of said filter to said drain pump for discharge through said drain outlet, and a motor mounted below said drain pump and having a vertically extending shaft connected to drive the impellers of both said main pump and said drain pump so that both said pumps are operative simultaneously during the drain period to provide a flushing action of the chamber and said fine filter.

2. A liquid distributing system as defined in claim 1 wherein an annular shaped removable coarse strainer surrounds said fine filter and engages the sump to prevent large insoluble food particles from entering said drain pump.

3. An improved liquid distributing system as defined in claim 1 wherein an automatically operated valve is connected to said drain outlet for controlling the flow of liquid from said chamber.

4. A liquid distributing system as defined in claim 1 wherein said manifold means includes a cylindrical outlet portion adapted to receive a cylindrical inlet hub portion of said spray arm, and a floating sealing ring carried within a circumferential groove formed in one of said portions to prevent seepage of liquid between the clearance gap defined between said portions.

5. A liquid distributing system as defined in claim 1 wherein said main pump impeller includes engaging means on the bottom side to drive said drain impeller, and drive means mounted on the top end of said shaft to drive said main impeller to provide for easy removal of both said impellers from within the chamber.

6. An improved liquid distributing system for a dishwashing machine having a tank defining a cleansing chamber with a sump at the bottom and adapted to separate fine food particles from the liquid recirculated within the chamber, said system comprising, a main recirculating pump mounted within the sump and having a centrifugal impeller positioned with a vertical axis of rotation, means defining an inlet opening spaced above said impeller, a reaction spray arm spaced above said main pump and including a hub portion, manifold means connected to said pump and rotatably supporting said hub portion of said arm with a vertical axis of rotation, a frusto-conical shaped fine fitter surrounding said manifold means and said inlet opening and having a smaller portion adapted to extend above the dynamic water level within the sump and adjacent said hub portion of said arm, a drain pump spaced below the sump and including an impeller and means defining a drain outlet, means defining a passageway connecting the sump to said drain pump impeller and adapted to direct liquid containing relatively large food particles flushed downwardly and outwardly along the outside of said filter to said drain pump for pump for discharge through said drain outlet, and a motor mounted below said drain pump and having a vertically extending shaft connected to drive the impellers of both said main pump and said drain pump so that both of said pumps are operative simultaneously during the drain period to glrovide a flushing action of the chamber and said fine ter.

7. An improved liquid distributing system for a dishwashing machine having a tank defining a cleansing chamber with a sump at the bottom and adapted to separate fine food particles from the liquid recirculated within the chamber, said system comprising, a main recirculating pump mounted within the sump and having a centrifugal impeller positioned with a vertical axis of rotation, means defining an inlet opening spaced above said impeller, a

reaction spray arm spaced above said main pump and including a hub portion, means defining a circular opening in the bottom of said hub, a manifold connected to said pump and having an upper portion extending into said circular opening for rotatably supporting said arm with a vertical axis of rotation, means defining an annular groove formed within the exterior surface of said upper portion of said manifold, a ring seal spaced within said groove and adapted to engage the means defining said circular opening in said hub to eliminate substantially all seepage of liquid between said hub and said manifold upper portion, a filter surrounding said manifold means and said inlet opening and having a portion adapted to extend above the dynamic water level within the sump, a drain pump spaced below the sump and including an impeller and means defining a drain outlet, means defining a passageway connecting the sump to said drain pump impeller and adapted to direct liquid containing food particles flushed down the outside of said filter to said drain pump for discharge through said drain outlet, and a motor mounted below said drain pump and having a vertically extending shaft connected to drive the impellers of both said main pump and said drain pump so that both of said pumps are operative simultaneously during the drain period to provide a flushing action on the chamber and said fine filter.

8. An improved liquid distributing system for a dishwashing machine having a tank defining a cleansing chamber with a sump at the bottom and adapted to separate fine food particles from the liquid recirculated within the chamber, said system comprising, a main recirculating pump mounted within the sump and having an impeller positioned with a vertical axis of rotation, means defining an inlet opening spaced above said impeller, a reaction spray arm spaced above said main pump, manifold means connected to said pump and rotatably supporting said arm with a vertical axis of rotation, a fine filter surrounding said manifold means and said inlet opening and having a portion adapted to extend above the dynamic water level within the sump, a drain pump spaced below the sump and including an impeller and means defining a drain outlet, means defining a passageway connecting the sump to said drain pump impeller and adapted to direct liquid containing relatively large food particles flushed down the outside of said filter to said drain pump for discharge through said drain outlet, a motor mounted below said drain pump and having a vertically extending shaft connected to drive simultaneously the impeller of said main pump for recirculating liquid within the chamber and the impeller of said drain pump for removing liquid from the sump so that both of said pumps are operative simultaneously during the drain period to provide a flushing action of the chamber and said fine filter, and solenoid valve means in fluid communication with said drain outlet for stopping the flow of liquid through said drain outlet according to a predetermined wash and rinse cycle.

9. An improved liquid distributing system for a dishwashing machine having a tank defining a cleansing chamber with a sump at the bottom and adapted to separate fine food particles from the liquid recirculated within the chamber, said system comprising, a main recirculating pump mounted within the sump and including a housing defining diametrically opposed volutes formed therein and a centrifugal impeller positioned with a vertical axis of rotation, means defining a top axial inlet opening spaced above said impeller, a reaction spray arm spaced above said main pump and including a hollow hub means defining a cylindrical opening in the bottom of said hub, means defining an annular groove in the bottom surface of said hub, a manifold having twin conduits in fluid communication with said volute of said pump and having an upper cylindrical portion extending into said cylindrical opening of said hub, shaft means for rotatably supporting said arms with a vertical axis of rotation, means defining a groove formed within the exterior surface of said upper cylindrical portion of said manifold, a floating ring seal spaced within said groove and adapted to engage said means defining said cylindrical opening in said hub to eliminate substantially all seepage of liquid between said hub and said manifold upper portion, a fine conical shaped filter surrounding said manifold means and said inlet opening and having a portion adapted to extend above the dynamic water level within the sump, lip means on the top of said filter and spaced within said groove in said hub to provide a labyrinth seal between said filter and said hub, a drain pump spaced below the sump and including an impeller and means defining a drain outlet, passageway means connecting the sump to said drain pump impeller and adapted to direct liquid containing relatively large food particles flushed down the outside of said filter to said drain pump for discharge through said drain outlet, and a motor mounted below said drain pump and having a vertically extending shaft connected to drive said impellers of both said main pump and said drain pump so that both of said pumps are operative simultaneously during the drain period to provide a flushing action of the chamber and said fine filter.

10. An improved liquid distributing system for a dishwashing machine having a tank defining a cleansing chamber with a sump at the bottom, comprising a high pressure main recirculating pump mounted within the sump and having a centrifugal impeller positioned with a vertical axis of rotation, means defining an inlet opening spaced above said impeller to provide for a smooth and uniform flow of liquid to said impeller, a reaction spray arm spaced above said main pump, said spray arm including four equally spaced radially extending discharge tubes, means defining a plurality of jet openings in each tube with each jet opening spaced a predetermined distance from the center of said arm to provide a uniform spray coverage, manifold means connected to said pump and rotatably supporting said arm with a vertical axis of rotation, a drain pump spaced below the sump and including an impeller and means defining a drain outlet, means defining a passageway connecting the sump to said drain pump impeller, and a motor mounted below said drain pump and having a vertically extending shaft connected to drive the impellers of both said main pump and said drain pump so that both of said pumps are operative simultaneously to provide a flushing action of the chamber during the drain period.

References Cited UNITED STATES PATENTS 1,637,376 8/1927 Gibney 134-56 2,734,520 2/1956 Abresch et al 134-111 X 2,862,510 12/1958 Geiger et a1. 134-111 3,079,094 2/1963 Brezosky et al. 134-115 X 3,126,025 3/1964 Aubert et al 134-111 X 3,179,307 4/1965 Duncan et al 134-148 X 3,217,884 11/1965 Long 134-111 X 3,265,311 8/1966 La Flame 239-251 FOREIGN PATENTS 234,455 11/ 1925 Great Britain.

CHARLES A. WILLMUTH, Primary Examiner.

R. L. BLEUTGE, Assistant Examiner. 

10. AN IMPROVED LIQUID DISTRIBUTING SYSTEM FOR A DISHWASHING MACHINE HAVING A TANK DEFINING A CLEANSING CHAMBER WITH A SUMP AT THE BOTTOM, COMPRISING A HIGH PRESSURE MAIN RECIRCULATING PUMP MOUNTED WITHIN THE SUMP AND HAVING A CENTRIFUGAL IMPELLER POSITIONED WITH A VERTICAL AXIS OF ROTATION, MEANS DEFINING AN INLET OPENING SPACED ABOVE SAID IMPELLER TO PROVIDE FOR A SMOOTH AND UNIFORM FLOW OF LIQUID TO SAID IMPELLER, A REACTION SPRAY ARM SPACED ABOVE SAID MAIN PUMP, SAID SPRAY ARM INCLUDING FOUR EQUALLY SPACED RADIALLY EXTENDING DISCHARGE TUBES, MEANS DEFINING A PLURALITY OF JET OPENINGS IN EACH TUBE WITH EACH JET OPENING SPACED A PREDETERMINED DISTANCE FROM THE CENTER OF SAID ARM TO PROVIDE A UNIFORM SPRAY COVERAGE, MANIFOLD MEANS CONNECTED TO SAID PUMP AND ROTATABLY SUPPORTING SAID ARM WITH A VERTICAL AXIS OF ROTATION, A DRAIN PUMP SPACED BELOW THE SUMP AND INCLUDING AN IMPELLER AND MEANS DEFINING A DRAIN OUTLET, MEANS DEFINING A PASSAGEWAY CONNECTING THE SUMP TO SAID DRAIN PUMP IMPELLER, AND A MOTOR MOUNTED BELOW SAID DRAIN PUMP AND HAVING A VERTICALLY EXTENDING SHAFT CONNECTED 